Electrical system



March 18, 1947. K, STIEFEL 2,417,452

ELECTRICAL SYSTEM Filed Jan. 17, 1944 3 Sheets-Shut 1;

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Mai'ch 18, 1947. K. J. STIEFEL 2,417,452

ELECTRICAL SYSTEM Filed Jan. 17, 1944 3 Sheets-Sheet 3 P an. is. 1941UNITED STATES PATENT OFFICE 7 ELECTRICAL SYSTEM m1 1. Stiefei, Waltham,Masa, acalgnor to Raytheon Manufacturing Company, Newton, Man, acorporation of Delaware Application January 17, 1944, sci-m a... 518,853

charging a condenser. In systems of this kind the condenser is chargedto a high voltage of the order of twenty thousand to thirty thousandvolts, for example. All of the power which is stored in the condenserhas been supplied from a charging source which must deliver thenecessary power to the condenser at this high voltage. This imposes asevere burden on the source, particularly since such source usuallyinvolves a.

-rectifier tube system. Thus, such arrangements have necessitated theuse of complicated and expensive power supply sources capable of meetingthe foregoing severe requirements.

An object of this invention is to devise a system of the above generaltype in which the power and voltage which the condenser charging systemis called upon to deliver are substantially reduced.

Another object is to deliver energy to the condenser only partially fromthe charging system and to supply the rest of the energy to thecondenser in the form of mechanical energy.

In such systems it is also desirable to produce a pulse having asubstantially rectangular wave form. Therefore, another object of. thisinven= tion is to devise such a system in which such a rectangular waveshape is approximated much more closely than in the prior systems.

A further object of this invention is to devise systems of the foregoingnature which are of a simple, compact and reliable structure.

The foregoing and other objects of this invention will be bestunderstood from the following description of exemplifications thereof,reference being had to the accompanying drawings wherein:

Fig. 1 is a diagram of one form of the invention showing the condenserassembly in crosssection; i

Fig. 2 is a cross-section taken along line 22 of Fig. l; a

Fig. 3 is a cross-section taken along line 3-3 of Fig. l;

Fig. 4 is a circuit diagram of the arrangement as shown in Fig. 1;

Fig. 5 is a view similar to Fig. 1 of another embodiment oi the presentinvention;

Fig. 6 is a cross-section taken along line 8-3 of Fig. 5;

Fig. 'l is a cross-section taken along line 1-1 of F18. 5;

10 Claims. (oi. 171-97) Fig. 8 is a cross-section taken along line 3-3of Fig. 5; and

Fig. 9 is a circuit diagram of the arrangement as shown in Fig. 5.

In the arrangement shown in Figs. 1-4, pulses of current each ofsubstantially rectangular wave shape are to be supplied periodically toa load i which may be, for example, a magnetron oscillator. Each pulseis produced by the discharge of a condenser energy storage assembly 2.The charging current for the condenser 2 is supplied from a pair ofterminals 3 which are adapted to be connected to a suitable source ofcurrent. This source may constitute either an alternating current or adirect current source. One of the terminals 3 is directly connected to acontact terminal 4 on the condenser assembly 2. The other terminal 3 isconnected through a choke Ii in series with a rectifier tube 6 toanother contact terminal I on the condenser assembly 2. If a directcurrent source is connected between the terminals 3 it is polarized sothat the positive pole thereof is connected to the lead which ex-' tendsto the anode of tube 3, whereby said tube tends to conduct current fromsaid source to charge the condenser assembly. If an altemating currentsource is used the rectifier 6 will ordinarily conduct during eachalternate half cycle thereof.

The condenser assembly 2 comprises a sealed envelope 3 whose walls arecomposed of a suitable insulating material, such as glass. Through thewalls of the envelope 8 are sealed a plurality of condenser plates 9.These plates are spaced from each other so as to provide between eachpair of plates a segmental opening of substantially the same size andshape as an adjacent condenser plate 9. Each of the plates 9 has anexterior portion ill to which an external electrical connection may bemade. The contact terminal 7 I may be connected to one of the externalportions M. It will be noted that in the example shown the condenserplates 9 are arranged in four horizontal sets, the plates of eachhorizontal set being aligned with the plates of each of the otherhorizontal sets. Furthermore, each horizontal set consists of fourcondenser plates 9 equally spaced from each other, as explained above.The condenser assembly 2 also is provided with a rotor member comprisinga plurality of condenser rotor plates. i i. Each of these condenserrotor plates ii is interposed between two adjacent horizontal sets ofthe condenser stator plates 9. Each of the condenser plates II has aplurality of sector shaped arms corresponding in size, numit and id. Thebearing it may be supported by being fused into the lower wall of theenvelope ii. The bearing id is hermetically sealed to the center of aflexible diaphragm is which in turn.

' is sealed in a central opening in a cap member It. This cap member issealed in the upper end of the envelope e and constitutes the upper wallof said envelope; In this way the envelope e is hermetically sealed sothat the interior thereof .may be filled with a gas, preferably at ahigh pressure of the order of several atmospheres, to

provide a proper dielectric material between the condenser plates and M.The gas pressure is sufliciently high and the condenser plates 9 and Iit are spaced a suficient distance from each other so that breakdown ofthe gaseous medium between the condenser plates ll and ii does not occurat the maximum voltage impressed upon the condenser. An auxiliary thrustmember ill is threaded on to the exterior of the cap member iii. Theauxiliary member H is provided with a central opening in which isjoumaled an ad- Justing member it. The bearing member iii oarries theexternally threaded contact terminal ii. The externally threaded portionof the contact terminal 4 is received ina threaded opening extendingcentrally through the adjusting member l8. Thus, as the adjusting memberI8 is rotated the position of the bearing 16 is correspondingly adjustedso as to maintain a proper pressure on the ends of the shaft. 12. Inthis way variations which otherwise mightoccur, due to temperature andexternal pressure. changes, can be compensated for.

In order to connect the condenser plates 9 in a proper network, each ofthese plates is connected to the'adjacent plate in its horizontal set byan induction 0011 I9 (Fig. 2). Likewiseeach condenser plate 9 isconnected to its adjacent vertically aligned condenser plate 9 byaninduction coi120 (Fig. 1).

In order to rotate the condenserv rotor the shaft,l2 carries a magneticarmature 2|, the

ends of which are spaced a distance from the lower inside walls of theenvelope 8. Outside of the envelope 8 is disposed a driving magnet 22having its poles 23 disposed adjacent the ends ofthe i2 also carries aplurality of distributorarms 28 corresponding in number to the number ofopeningsbetween the horizontal condenser, plates 9, with each aligned soas to lie between two of the arms of a condenser plate ii. A sparkingelectrode 29 i supported by a lead-in conductor 3 sealed through thewallof the envelope ii. The sparking electrode 29 is placed over the centerof one of the condenser plates 9 and is located so that the end of eachdistributor arm 28 passes said sparking electrode 29 with a very smallspacing therefrom, as the shaft i2 rotates. This spacing is sumcientlyclose so that the gap between each distributor arm and the sparkingelectrode 29 breaks down and permits the condenser assembly to dischargeeach time a distributor arm it passes the sparking electrode 20. Thelead-in conductor fit is connected to one of the electrodes of themagnetron i, for example, its cathode iii. A conductor'iiii connects theother .electrode of the magnetron i, for example its anode 333, to thecontact terminal 71.

The operation orthe arrangement as described voltage of the source maybe of a suitably high .value, for example, of the order of 3000 volts.

Thereupon a charging current will flow through the choke ii and therectifier t to the condenser assembly. Due to the action of'the choke 5in storing energy in its magnetic field during the building up of thecharging current and delivering said energy to the condenser during thedecay of the charging current, the condenser assembly will be chargedsubstantially to double the voltage of the source, for example, to avoltage of the order of 6000 volts. As the charging current falls tozero, the rectifier tube 6 stops conducting current and thereforedisconnects the condenser from the charging system until said condenseris subsequently discharged. The time constant of the charging system issuch that the above described charging is completed when the condenserplates II and 9 are substantially in alignment with each other. When thecondenser-plates I! move away from the condenser plates 9 to a positionof alignment with the openings between said condenser plates 9, work isdone against the force of the electrical field existing between theplates H and 9, which force tends to move said plates toward each other.manifests itself as an increase in the voltage on the condenserand'acorresponding increase in the energy stored therein.

The'nature of the above increase will be more clearly understood fromthe following considerations. Separating the plates of a condenserdecreases the capacity of the condenser proportionately to theseparation. The voltage E across In order to secure a good electricalcontact I with the condenser rotor, the shaft I2 carries a contact ring26 upon which bears a contact brush 2'! supported by and electricallyconnected to the bearing l4 and its associated contactterminal 4.

It is intended that the condenser system shall be discharged at the timewhen the condenser plates II are aligned with the openings between thecondenser plates 9. For this purpose the shaft a capacity, C can beexpressed as 4 where Q is the quantity of electricity stored in thecapacity. Since separating the plates of a condenser does not change thequantity of electricity stored therein, it will be seen that the voltageacross the condenser increases proportionately as the capacitydecreases. The energy (stored in a condenser can be expressed as Thework thus done required by the device.

From the above it can be shown that the energy stored in the condenserincreases proportionately with the decrease in the capacity. In apractical case the final capacity can be decreased to about one quarterof the initial capacity. This will cause the final voltage to rise tofour times the initial voltage and the final energy stored in thecondenser will be four times the initial energy supplied thereto by thecharging circuit. This means that the motor 24 will supply three fourthsof the final total energy stored in the condenser, while the powersupply 3-3 will supply only one fourth of that energy. In the particularexample as cited above, of the voltages involved, .the final voltageacross the condenser assembly will be of the order of 24,000 volts.

As pointed out above the distributor arms 26 are arranged so as to causethe gap between each of the said arms and the sparking electrode 26 tobreak down when the condenser plates II are aligned with the openingsbetween the con-- denser plates 9. Thus, this breakdown and discharge ofthe condenser will occur each time the maximum voltage across thecondenser is reached during each rotation of the condenser rotor. Uponeach such discharge the condenser will supply a pulse of current ofcomparatively short duration, but of relatively high power to the loadl. After each discharge of the condenser the rectifier 6 will againstart to conduct current and connect the condenser 2 to the source so asto again charge said condenser to its initial value. As pointed outabove the time constants of the charging system are such thatthe'charging of the condenser is completed when the plates 9 and H areagain in alignment with each other. Thus, in the example illustrated thevoltage across the condenser I2 rises and falls four times during eachrevolution of the condenser rotor and thus four distributor arms 26 willbe provided to produce four discharge pulses through the load I. Fromthe above it will be seen that the power supply connected to theterminals 3-3 need deliver only a fraction of the voltage and power Thussuch an arrangement relieves the power supply of the conditionspreviously imposed upon it and thus enables the use of a much simplerand more reliable arrange-.

ment than has heretofore been practicable.

As previously indicated, it is desirable that the wave shape of thecurrent pulse supplied to the load I be substantially rectangular. Thecombination of individual condensers and inductances of the condenserassembly 2 comprises a pulse line.

If a pulse line comprises a plurality of sections each consisting of apair of condensers connected across the line with an inductanceinterposed in one'of the lines between said condensers, the wave shapederived from such a line would become more nearly rectangular as thenumber of said sections increased. Ordinarily the complexity ofstructure and size involved in securing a large number of such sectionsare so great that the art has heretofore resorted to only a few pulseline sections with a consequent sacrifice in the wave shape. However, asshown by the circuit diagram in Fig. 4 the arrangement illustrated inFig. l-produces, in a comparatively small space, a large number of'pulseline sections arranged in a complex network. A pulse line of this typeproduces a pulse wave shape which almost perfectly approximates arectangle. It will be seen that this effect is independent of therotation of the condenser rotor. Thus a construction of this type couldalso be used in a fixed condenser to secure the advantages of animproved pulse wave shape.

The arrangement as described above lends itself not only to a system inwhich a gas dielectric is used, but also to one in which the spacebetween the plates II and 6 is a, high vacuum. In such an arrangementthe interior of the envelope 6 would be highly evacuated. However, insuch an arrangement by properly configuring and spacing the distributorarms 26 from the sparking electrode 26, a discharge can be made to occurbetween said members in a vacuum whenever an arm 26 passes the electrode29.

Another form of this invention is illustrated in Figs. 5 to 9, whichform lends itself particularly to a system for producing a large numberof short impulses having a high repetition rate. In Figs. 5-9, the samereference numerals are applied as in Figs. 1-4 where the elements areidentical. In Figs. ,5-9, the entire pulsing system, including thedriving motor, is entirely enclosed within a casing 34 of some suitableinsulating material. Spaced within this casing is a motor 35 comprisinga stator 36 and a rotor 31 mounted upon a shaft 38. The shaft 38 is madeof a good conducting material to which electric contact is insured by acontact ring 39 carried by the shaft 38 and engaged by a brush 40. Thebrush 46 is carried by the stator 36 and connected to a terminal 4|sealed through the wall of the casing 34. The motor 35 may be suppliedwith current through a cable 42 likewise sealed through the wall of thecasing 34. Mounted on the outside of the stator 36 is an insulatingsleeve 43. Secured to the outer surface .of this insulating sleeve are aplurality of condenser plates 44 in the form of longitudinally disposedconducting strips. Each condenser plate 44 is spaced from its adjacentcondenser plate 44 by a distance substantially equal to the width of oneof said condenser plates. The condenser plates 44 are connected to eachother by a plurality of induction coils 45. A plurality of similarcondenser plates 46 are secured to the inside of the casing 34. Eachcondenser plate 46 is disposed opposite one of the condenser plates 44.The condenser plates 46 are likewise connected to each other by aplurality of induction coils 41. Each condenser plate 46 is likewiseconnected to its adjacent condenser plate 43 by an inducttion coil 48. IThe condenser plates 43 and 46 form the stator of a rotating condenser,an annular space existing between said condenser plates in which therotor of said condenser is adapted to rotate. The condenser rotorcomprises a cup 49 of insulating material. On the outside walls of thecup 49 are secured a plurality of condenser plates. 50 likewisecomprising longitudinal strips spaced from each other as described inconnection with the plates 44. On the inside walls of the insulating cup49 are secured similar condenser plates 5|, each plate 5i being locatedadjacent one of the condenser plates 50. Each pair of condenser plates50 and 5! are connected to each other over the lower end of the cup 49by a. connector 52. The condenser plates 50 and 5| correspond in size,number and spacing to the condenser plates 44. Each condenser plate 50is connected by a connector 63 extending over the top of the cup 46 to acentral hub connector 64 which is in turn electrically connected to theshaft 38. One of the condenser plates 46 is electrically connected to alead-in terminal 55 sealed through the wall of the casing 34. Aconvenient way to form the condenser plates described above is to platethe ma- 1 terial forming said plates on to the surface or the insulatingwalls. The rotating condenser ar rangement is here likewise providedwith a plurality of distributor arms 56 carried by and electricallyconnected to the shaft 38. These dis= tributcr arms are each locatedbetween two of the condenser plates Bil. A sparking, electrode 57 iscarried by a, lead-in terminal 68 sealed through'the upper wall of thecasing 36. This connection with the arrangement of Fig. i, so as toproduce a discharge between a distributor arm 52 and the sparkingelectrode 5? each time said distributor arm passes adjacent saidsparking electrode. in this case likewise the casing M is.

filled with a gas, preferably at high pressure, as described inconnection with Fig. l.

The operation of the system, as illustrated in Figs. 5-9, issubstantially identical to that do scribedin connection with theembodiment illustrated in Figs.' l-4. In this second embodiment thecondenser assembly likewise constitutes a complex pulse line network asshown by the cir= cuit diagram in Fig. 9. Here likewise the pulse hnewill deliver'a pulse'having a wave shape which closely approximates arectangle. Although this embodiment has been illustrated with fourcondenser sections, it is to be understood that such an arrangement-isadapted for the use of a'considerably large number of such condensersections in order to obtain a rapid repetition rate of pulsing. Oneexample of an arrangement of this kind might consist of a high speedmotor operating at 12,000 R; P.-M., and-a condenser having six sections.Under these conditions 1200 tional condenser elements each having aplurality of arm sections disposed concentrically around said firstcondenser element, each of said arm sections being connectedto anadjacent arm of its condenser element section by an inductance, each. ofsaid am sections also being connected to an arm section of another ofsaid condenser elements by an inductance.

a. An electrical system comprising a condenser comprising a condenserelement having a plurality of circularly disposed arms, said condenserelement being adapted to rotate about an axis, said arms being disposedsubstantially parallel to said axis, another condenser element having aplurality of arm sections disposed concentrically I around said firstcondenser element and substantially parallel tosaid arms, said amsections being spaced from each other to form intervening spaces, meansfor rotating said condenser elements with respect to each other to causesaid arms alternately to be aligned with said varn' sec tions and withsaid spaces, and means for discharging said condenser when said arms andarm elements are out of alignment with each other.

5. An electrical pulse-forming system comprising: at least two parallelconnected condensers; an'inductor connectedin series with each adjacentpair of said condensers; means for charging said condensers to apredetermined voltage; means for decreasing the capacitance of saidcondensers after they have been charged, and thereby increase thevoltage across the same; and means for discharging said condensers aftersaid capacitance has been decreased to a predetermined minimum value.

6. An electrical pulse-forming. system comprising: at least two parallelconnected condensers, each of which includes a fixed plate and amovpulses per second would be deliveredto the load.

Of course itis'to be understood that thisinvention is not limited to theparticular details as described above-as many equivalentswill suggestthemselves to those skilled in the art. It is ac cordingly desired thatthe appended claims be given a. broad interpretation commensurate withthe scope of the invention within the art.

What is claimed is:

( 1. An electrical system comprising rality of circularly disposed arms,another condenser element having a plurality of arm sections disposedconcentrically around said first cona condenser comprising a condenserelement having a pluable plate; an inductor connected in series witheach adjacent pair of said condensers; means for charging saidcondensers to a predetermined voltage; means for moving said condenserplates relative to each other to decrease the capacitance of saidcondensers after they have been charged, and thereby increase thevoltage across the same and meansfor discharging said condensers aftersaid capacitance has beendecreased to a prede termined minimum value.

7;. An electrical pulse-forming system comprising: atleast two parallelconnected condensers, each of which includes a fixed plate and amovable; plate; each such fixed plat consisting of a =Iplurality ofplatesections connected by inductors, and each such movable plateconsisting of a plufor charging said condenser to a vpredeterminedvoltage when said arms and arm sections are in alignment, means forrotating said condenser elements with respect to each other, and meansfor discharging said condenser when said arms and arm elements are outof alignment with each other.

2. An electrical energy storage system comprising a condenser elementhaving a plurality of circularly disposed arms, and another condenser Yelement having .a plurality of arm sections disposed concentricallyaround said first condenser element, each of said arm sections beingcon-.

nected to an adjacent arm section by an inductance.

3. An electrical energystorage system compris- *ing a condenser elementhaving a plurality of 1 charged, and thereby increase the voltage across"the same; and means operating in synchronism 'rality of connected platearms cooperable, respectively, with said plate sections; an inductorconnected in series with each adjacent pair of said condensers; meansfor charging said condensers to a predetermined voltage; means formoving said condenser plates'relative to each otherto decrease thecapacitance of said condensers after they have been charged, and therebyincrease the voltage across the same; and means for discharging said'condensers after said capacitance v has been decreased to apredetermined minimum value.

'8. An electrical pulse-forming system comprising: at least two parallelconnected condensers; an inductor connected in series with each adjacentpair of said condensers; meansforperiodically charging said condensersto a predeterminedvoltage; means for decreasing the capacitance of saidcondensers after they have been with said capacitance decreasing meansfor discharging said condensers .atter saidqcapacitance has beendecreased to a predetermined minimum value.

9. An electrical pulse-forming system comprising: at least two parallelconnected condensers,

each of which includes a fixed plate and a movable plate; an inductorconnected in series with each adjacent pair or said condensers; meansfor periodically charging said condensers to a predetermined voltage;means ior moving said condenser plates relative tc each other todecrease the ca- 4 pacitance of said condensers after they have beencharged, and thereby increas the voltage across the same; -and meansoperating in synchronism with said plate-moving means for dischargingsaid condensers after said capacitance has been decreased to apredetermined minimum value.

tiveto each other to decrease the capacitance of said condensers afterthey havebeen charged, and thereby increase the voltage across the same:

' and means operating in synchronism with said plate-moving means fordischarging said con- 10. An electrical pulse-forming system comprising:at least two parallel connected condensers. each of which includes afixed plate and a movable plate: each such fixed plate consisting of aplurality oi plate sections connected by Number densers after saidcapacitance has been decreased toa predetermined minimum value.

KARL J. STIEFEL anrnaancns crmn The following references are of recordin the ille of this patent:

UNITED B'IATEB m'rmrrsg Name 4 Date 1,559,656 Thorp Nov. s, 1925

